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From: woody@chinacat.Unicom.COM (Woody Baker @ Eagle Signal)
Newsgroups: comp.lang.postscript
Subject: Re: Disk cache? [was Re: Obscure LaserWriter features}
Summary: but but but...
Message-ID: <1551@chinacat.Unicom.COM>
Date: 7 Sep 90 02:16:07 GMT
References: <1546@chinacat.Unicom.COM> <428@macuni.mqcc.mq.oz> <1990Sep5.211829.4130@Neon.Stanford.EDU>
Organization: a guest of Unicom Systems Development, Austin
Lines: 30

In article <1990Sep5.211829.4130@Neon.Stanford.EDU>, philip@pescadero.Stanford.EDU (Philip Machanick) writes:
> > up, as you can use the disk as a *VERY* large print buffer...
> large amount of slow memory. For the price of an external 20M SCSI disk, you
> could probably buy about 4M of RAM. I would guess in most practical
> applications, increasing the amount of RAM sould be a more effective
> way of speeding things up (RAM access time: about 100ns; disk access time:

Considering that few printers are expandable that way, those that are
would see an increase in speed.  Note:  on most implementations the font
cache is more or less static.  You have no way of partitioning memory
(unfortunatly).  I wish that PS had a mechanism that would allow you
to balance VM vs Font cache.

> around 20ms - 200 times slower, if my arithmetic is right; not the whole
Yes, but consider the following:

I have a book that consists of about 100 or so pages.  Say something
like the RED book in size.  The postscript code to describe these pages
resides on my hard disk.  Give the normal limited input buffer (again
I wish there was a way to partition more memory to this as needed). it
is going to take quite a while at even 19200 or centronics to transfer
this.  If I could dump it over the scsi port at say 5 megs per second
or whatever it is that the scsi port can handle, and store it on the
hard disk, then my transmission time drops to almost nothing, and
while it might take an hour or two to print the book, it should only
take very few min to transmit it.  Increasing the memory is not going
to help in this case.  This is what I was refering to.  :=}

Cheers
Woody